Trailer side marker lights For You: What You Need to Know

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You probably don’t give much thought to the side marker lights on your trailer very frequently, but when the time comes when you need them, they’ll become your new best buddy. What side marker lights, you ask? They are little lights that may be either yellow or white and are put on the side of your trailer.

These lights allow other drivers to see you more clearly and help lessen the danger of being involved in a mishap while backing up or driving in the blind area of another vehicle. While visibility is poor, such as when driving at night or when backing up, the side marker lights will turn on automatically to warn other vehicles of your location and avoid accidents.  

What Are The Rules Regarding The Use Of Side Marker Lights For Trailers?

Your vehicle’s electrical system is responsible for controlling the trailer side marker lights, and integrated controls inside the car are used to operate them. They have to fulfill the minimal photometric standards specified in SAE J594 at the very least. A switch that can turn the lights on and off must be installed inside the trailer.

The wiring of the trailer side marker lights has to be done so that electricity is supplied to the lights whenever any of the following is operational: The electronic braking system of the trailer has been engaged. The parking brake on the tow vehicle is applied, the ignition switch is turned on, either the transmission of the towed vehicle is in gear, or it is in neutral, and the parking brake is applied on the tow car. 

Why Is It Necessary To Have?

You’ll find side marker lights, which may be either yellow or white, on the sides of trailers, fifth wheel hitches, and even sure truck beds. These lights can also be found in some truck cabins. They serve to alert other drivers to the presence of a trailer in conditions with limited vision, such as during bad weather, at night, or while driving in confined areas.

Except for utility trailers and trailers with a Gross Trailer Weight (GTW) rating of fewer than 3,000 pounds, these lights must be installed on all trailers. If you want to drive your trailer on a public road, you are the one who is responsible for ensuring that it is equipped with side marker lights.

Tutorial On How To Install Side Marker Lights On A Trailer

First, check that you have all of the necessary equipment. You will need a multimeter, electrical tape, a crimping tool, and a wire remover to do this task. In addition to this, you will need to choose a wiring diagram tailored to your particular car. Utilizing this chart, you will be able to determine where to connect your wire. The next step is to strip your wires.

To connect the wire to the rest of the car’s wiring, you will need to strip away part of the insulation on its end. Crimping is used to attach the wires. Make sure the cable length is enough for crimping and taping. Make that the wires for the taillights and side markers are connected. When the turn signals are activated, the headlights should also be turned on, and vice versa.


Even though you probably don’t give much thought to the side marker lights on your trailer very frequently. They are vitally crucial for ensuring the safety of both you and others around you. When you’re driving on the road or in any circumstance with limited visibility, turning these lights on might differ between getting into an accident and getting by unscathed.

When you’re backing up your trailer, putting side marker lights on it may make all the difference in the world. Whether you’re on the road, in a parking garage, or simply backing up, this is true. However, since there are so many distinct kinds of lights available, choosing which ones to purchase may be challenging.

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